1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a data recording apparatus and a method of manufacturing the same and, more particularly, to a magnetic recording head and a method of manufacturing the same.
2. Description of the Related Art
Magnetic recording media can be classified into longitudinal magnetic recording media and perpendicular magnetic recording media according to whether magnetization is longitudinal or perpendicular to a surface of a recording medium. As the demand for recording media with higher data recording density increases, increasing attention is being directed toward perpendicular magnetic recording media. Because a magnetic recording medium is very closely related to a magnetic recording head, as attention toward perpendicular magnetic recording media increases, attention toward a magnetic recording head used in writing data on a perpendicular magnetic recording media is also increasing. A main pole and a return pole in a magnetic recording head are used in writing data directly on a magnetic recording medium. Thus, the stability and excellence of a magnetic recording head are closely related to the return pole and the main pole and, in particular, the main pole.
FIG. 1 illustrates the relationship between a selected track 12 on which a magnetization pattern, that is, bit data is written and a rectangular main pole 10 used in a conventional magnetic recording head when a skew angle of the main pole 10 is 10°. Referring to FIG. 1, when the bit data is written on the selected track 12, a portion 10a of the main pole 10 deviates from the selected track 12.
FIG. 2 is a magnetic force microscopy (MFM) image of a bit data recorded on a perpendicular magnetic recording medium using the conventional magnetic recording head including the main pole 10 shown in FIG. 1. Reference numeral 14 in FIG. 2 indicates a magnetization pattern recorded on a periphery of the track 12 by the portion 10a of the main pole 10 deviating from the track 12 while a magnetization pattern is recorded by the main pole 10 of the magnetic head on the track 12. When a magnetization pattern is recorded on a track adjacent to the track 12, a wrong magnetization pattern is recorded on the track adjacent to the track 12 by the magnetization pattern 14. To prevent this problem, it is desirable to have the magnetization pattern 14 not to be recorded on a track adjacent to the track 12 while a magnetization pattern is recorded on the track 12. Thus, there is a need for a novel main pole not affecting recording on a track adjacent to a main track on which a magnetization pattern is recorded. FIG. 3 illustrates one of main poles introduced to satisfy this requirement. While the main pole 10 illustrated in FIG. 1 is rectangular, a main pole 18 illustrated in FIG. 3 has a trapezoidal shape tapering end to end. The main pole 18 is formed by removing a portion of the rectangular pole 10 illustrated in FIG. 1.
More specifically, when the main pole 10 is used to write a magnetization pattern on an inner track located interior to the track 12, a case opposite to that illustrated in FIG. 1 appears. That is, as the skew angle changes in the opposite direction, the portion 10a of the main pole 10 that was originally exposed outside the track 12 is then located within the inner track on which a magnetization pattern will be recorded while a lower portion of the main pole 10 that was originally located within the track 12 is then located outside the inner track 12.
To prevent unnecessary magnetization patterns from being recorded on a track other than a selected track, it is necessary to remove the portion 10a of the main pole 10 located outside the track 12 as well as the portion of the main pole 10 deviating from another selected track located interior to the track 12 when a magnetization pattern is recorded on the other selected track at a different skew angle.
Reference numeral 16a in FIG. 3 indicates a removed portion of the main pole 18 corresponding to the portion 10a of the main pole 10 exposed outside the track 12 when the main pole 10 shown in FIG. 1 having the skew angle of 10° writes a magnetization pattern on the track 12. Also, reference numeral 16b in FIG. 3 indicates a removed portion of the main pole 18 corresponding to the portion of the main pole 10 exposed outside the inner track when the main pole 10 shown in FIG. 1 is used to write a magnetization pattern on the inner track.
FIG. 4 illustrates a magnetization pattern recorded on a selected track 12 using the main pole 18 of FIG. 3. As is evident from FIG. 4, a magnetization pattern with alternating black and white lines is recorded on a selected track 12 only, not on a periphery of the track 12.
FIG. 5 illustrates a change in erase band width with respect to the geometrical shape of a main pole contacting a magnetic recording medium and a skew angle.
Referring to FIG. 5, when a portion of the main pole facing the magnetic recording medium has a rectangular shape (indicated by ▴), the erase band width increases as a skew angle increases. On the other hand, when the portion of the main pole is trapezoidal (indicated by ●), the erase band width does not increase as the skew angle increases.
FIGS. 6-9 illustrate a process of manufacturing a main pole and a return pole in a conventional magnetic recording head.
Referring to FIG. 6, an insulating layer 22 is formed on a NiFe magnetic layer 20 that will be used as a return pole. A photoresist pattern 24 is formed on the insulating layer 22 and defines a region where a main pole will be formed. Using the photoresist pattern 24 as a mask, the defined region of the insulating layer 22 is etched to form a groove 26 in the insulating layer 22 as illustrated in FIG. 7.
Referring to FIG. 8, a magnetic layer 28 is formed on the insulating layer 22 in which the groove 26 has been formed and fills the groove 26. The magnetic layer 28 is formed of a magnetic substance with high saturation magnetic flux density Bs. Referring to FIG. 9, a top surface of the magnetic layer 28 is polished until the insulating layer 22 is exposed to form a magnetic layer pattern 28a filling the groove 26. The magnetic layer pattern 28a is used as the main pole. An arrow in FIG. 9 indicates a direction in which a recording medium moves.
FIGS. 10-12 illustrate a method of manufacturing a conventional magnetic recording head with side shields on either side of a main pole in order to reduce the effect of a magnetic field generated by the main pole on adjacent tracks.
Referring to FIGS. 10 and 11, an insulating layer 22 is formed on a magnetic layer 20. Then, a photoresist pattern 30 is formed on the insulating layer 22 and defines a first region R1 in which a main pole will be formed and second and third regions R2 and R3 where side shields will be formed. Using the photoresist pattern 30 as a mask, a magnetic layer 32 is formed on the insulating layer 22 using an electroplating method. Referring to FIG. 12, the photoresist pattern 30 is then removed to form first through third magnetic layer pattern 32a through 32c. The first magnetic layer pattern 32a is used as the main pole while the second and third magnetic layer patterns 32b and 32c are used as side shields to prevent a magnetic field generated by the main pole 32a from extending to adjacent tracks.
Because the main pole 28a in the conventional magnetic recording head manufactured according to the steps illustrated in FIGS. 6-9 is formed using a photo process and an etching process, it is difficult to precisely control a distance between the main pole 28a and the return pole 20. Furthermore, for the conventional magnetic recording head manufactured using the method illustrated in FIGS. 10-12, in which the distance between the main pole 32a and one of the side shields 32b and 32c is determined by the photoresist pattern 30, the distance is eventually determined by the resolution of an exposure system used. Thus, it is also difficult to precisely control the distance between the main pole 32a and one of the side shields 32b and 32c. 